/*
 * Copyright 2016 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#ifndef SKSL_FIELDACCESS
#define SKSL_FIELDACCESS

#include "include/core/SkSpan.h"
#include "src/sksl/SkSLPosition.h"
#include "src/sksl/ir/SkSLExpression.h"
#include "src/sksl/ir/SkSLIRNode.h"
#include "src/sksl/ir/SkSLType.h"

#include <cstddef>
#include <cstdint>
#include <memory>
#include <string>
#include <string_view>
#include <utility>

namespace SkSL {
class Context;
enum class OperatorPrecedence : uint8_t;

enum class FieldAccessOwnerKind : int8_t {
    kDefault,
    // this field access is to a field of an anonymous interface block (and thus, the field name
    // is actually in global scope, so only the field name needs to be written in GLSL)
    kAnonymousInterfaceBlock
};

/* *
 * An expression which extracts a field from a struct, as in 'foo.bar'.
 */
class FieldAccess final : public Expression {
public:
    using OwnerKind = FieldAccessOwnerKind;

    inline static constexpr Kind kIRNodeKind = Kind::kFieldAccess;

    FieldAccess(Position pos, std::unique_ptr<Expression> base, int fieldIndex,
        OwnerKind ownerKind = OwnerKind::kDefault)
        : INHERITED(pos, kIRNodeKind, base->type().fields()[fieldIndex].fType),
          fFieldIndex(fieldIndex),
          fOwnerKind(ownerKind),
          fBase(std::move(base))
    {}

    // Returns a field-access expression; reports errors via the ErrorReporter.
    static std::unique_ptr<Expression> Convert(const Context &context, Position pos, std::unique_ptr<Expression> base,
        std::string_view field);

    // Returns a field-access expression; reports errors via ASSERT.
    static std::unique_ptr<Expression> Make(const Context &context, Position pos, std::unique_ptr<Expression> base,
        int fieldIndex, OwnerKind ownerKind = OwnerKind::kDefault);

    std::unique_ptr<Expression> &base()
    {
        return fBase;
    }

    const std::unique_ptr<Expression> &base() const
    {
        return fBase;
    }

    int fieldIndex() const
    {
        return fFieldIndex;
    }

    OwnerKind ownerKind() const
    {
        return fOwnerKind;
    }

    std::unique_ptr<Expression> clone(Position pos) const override
    {
        return std::make_unique<FieldAccess>(pos, this->base()->clone(), this->fieldIndex(), this->ownerKind());
    }

    size_t initialSlot() const;

    std::string description(OperatorPrecedence) const override;

private:
    int fFieldIndex;
    FieldAccessOwnerKind fOwnerKind;
    std::unique_ptr<Expression> fBase;

    using INHERITED = Expression;
};
} // namespace SkSL

#endif
